1. Field of the Invention
The present invention relates to a heat-sensitive transfer image-receiving sheet and more particularly to a heat-sensitive transfer image-receiving sheet for providing a good image having a high transfer density and little image unevenness.
2. Description of the Related Art
Various heat-sensitive transfer recording methods have been heretofore known. In particular, a dye dispersion transfer recording method has been noted as a process capable of preparing a color hard copy having the closest image quality to silver salt photograph (see the non-patent references below). Further, this dye dispersion transfer recording method is advantageous in that it can be operated in a dry process as compared with silver salt photography and allows direct visualization from digital data that facilitates reproduction.
In the dye dispersion transfer recording method, a heat-sensitive transfer sheet containing a dye (hereinafter referred to as “ink sheet”) and a heat-sensitive transfer image-receiving sheet (hereinafter referred to as “image-receiving sheet”) are laminated on each other. Subsequently, the ink sheet is heated by a thermal head which is controlled in heat generation by an electric signal so that the dye in the ink sheet is transferred to the image-receiving sheet to make recording of image data. Cyan, magenta and yellow colors are then recorded imposed on each other to make transfer recording of a color image having a continuous color density change.
The image-receiving sheet to be used in this process comprises a receiving layer formed on a support for receiving a dye which has been transferred. In general, in order to enhance the adhesion between the image-receiving sheet and the ink sheet, a layer having a high cushioning effect such as foaming layer made of a resin and a foaming agent and a porous layer containing a hollow polymer is formed between the support and the receiving layer (see JP-A-11-321128 and JP-A-2-89690).
For example, “Joho Kiroku (haado kopi) to sono zairyouno shintenkai (New Development of Data Recording (hard copy) and Its Materials)”, Toray Research Center, 1993, pp. 241-285 discloses that the spreading and drying of an interlayer comprising a hollow particulate material and an organic solvent-resistant polymer as main components on a support is followed by the formation of a receiving layer by an organic solvent-based resin coating solution. The organic solvent-resistant polymer to be incorporated in the interlayer acts to prevent the hollow particulate material incorporated in the interlayer from being dissolved in the organic solvent in the receiving layer. However, the heat-sensitive transfer image-receiving sheet comprising a receiving layer formed by an organic solvent-based resin coating solution is disadvantageous in that it has an insufficient sensitivity and a raised cost. The heat-sensitive transfer image-receiving sheet has been desired to have improvement also in image quality and transfer density.
“Purinta Zairyou no Kaihatsu (Development of Printer Materials)”, CMC, 1995, page 180 discloses a heat-sensitive transfer image-receiving sheet comprising a layer having a hollow spherical pigment dispersed therein and an image-receiving layer (receiving layer). However, this heat-sensitive transfer image-receiving sheet is disadvantageous in that the image obtained after transfer undergoes bleeding.